header fixes, and lazy queries

sandbox/will/basic.py

@@ -6,7 +6,7 @@ from rich.text import Text
 from textual.app import App, ComposeResult
 from textual.reactive import Reactive
 from textual.widget import Widget
-from textual.widgets import Static, DataTable, DirectoryTree, Footer
+from textual.widgets import Static, DataTable, DirectoryTree, Header, Footer
 from textual.layout import Vertical
 
 CODE = '''
@@ -112,17 +112,14 @@ class BasicApp(App, css_path="basic.css"):
         self.bind("s", "toggle_class('#sidebar', '-active')", description="Sidebar")
         self.bind("d", "toggle_dark", description="Dark mode")
         self.bind("q", "quit", description="Quit")
+        self.bind("f", "query_test", description="Query test")
+
+    def compose(self):
+        yield Header()
 
-    def compose(self) -> ComposeResult:
         table = DataTable()
         self.scroll_to_target = Tweet(TweetBody())
 
-        yield Static(
-            Text.from_markup(
-                "[b]This is a [u]Textual[/u] app, running in the terminal"
-            ),
-            id="header",
-        )
         yield from (
             Tweet(TweetBody()),
             Widget(
@@ -166,12 +163,30 @@ class BasicApp(App, css_path="basic.css"):
         for n in range(100):
             table.add_row(*[f"Cell ([b]{n}[/b], {col})" for col in range(6)])
 
+    def on_mount(self):
+        self.sub_title = "Widget demo"
+
     async def on_key(self, event) -> None:
         await self.dispatch_key(event)
 
     def action_toggle_dark(self):
         self.dark = not self.dark
 
+    def action_query_test(self):
+        query = self.query("Tweet")
+        self.log(query)
+        self.log(query.nodes)
+        self.log(query)
+        self.log(query.nodes)
+
+        query = query.exclude(".scroll-horizontal")
+        self.log(query)
+        self.log(query.nodes)
+
+        query = query.filter(".rubbish")
+        self.log(query)
+        self.log(query.first())
+
     async def key_q(self):
         await self.shutdown()